A remote center compliance (RCC) device provides a remote center of compliance at, near or beyond the free end of an operator means or member. The operator member with the remote center near its tip may perform or carry parts that perform various functions, e.g. docking, tooling, insertion, engaging.
The remote center of compliance is a point about which rotation of the operator member occurs and with respect to which translation of the operator member occurs. RCC devices have five degrees of freedom, rotation about the axis of the operator member, and rotation and translation along two mutually perpendicular axes orthogonal to the axis of the operator member.
RCC devices often carry at the free end of the operator member tools or other apparatus which may be quite heavy. If oriented horizontally, the weight at the free end of the operator member may cause the free end of the operator member to droop and rest on the support frame. In any orientation, the compliant structure of the RCC, especially with added weight, is highly susceptible to vibration and oscillation as it is moved about from one position to another. The oscillation or vibration not only makes it difficult to initiate the next task, but may become large enough to damage the RCC or other equipment.
One attempt to prevent these problems employs a control unit including a cylinder and piston which could be pneumatically driven to clamp the piston on to a conical jamming collet on the RCC and make rigid the RCC with its support frame. The control circuit is large, bulky and relatively heavy and requires substantial pressure and flow to operate. Further, it does not prevent the drooping of the free end or tip of the operator member, as the control unit only holds the body of the RCC device, not the tip of the operator member.